An internetwork is a collection of distinct computer networks connected using a common routing technology. The “Internet” is an example of such an internetwork, where communication between nodes in distinct networks is facilitated by an internetworking protocol standard, the Internet Protocol (IP) Suite.
The proper noun “Internet” (capitalized) refers to a global, publicly accessible system of interconnected packet switched networks that interchange data using the Internet Protocol Suite.
Internetworks which are not the “Internet” but which use the Internet Protocol Suite are sometimes referred to variously as an “internet”, “IP internetwork”, “private internet”, “private IP internetwork” or “private IP network”. That is to say, that the “Internet” is merely one example of an IP based internetwork, although it is a very popular one owing to its global and publicly accessible nature.
As is generally known in IP networks, in order for a node in an IP internetwork to send data to another node on the IP internetwork, the data must be encapsulated within an IP packet.
FIG. 1A is a block diagram of a computer network consistent with the prior art. As shown in FIG. 1A, Node 1, Node 2, Node 3 and Node 4 are all connected to a computer network 10. For data interchange to occur between networks, an internetwork is formed. The formation of an internetwork depends on the use of certain nodes, which are distinguished as gateway nodes that interconnect the networks. These interconnecting nodes may include, for example, “routers.”
FIG. 1B is a block diagram of an internetwork consistent with the prior art. As shown in FIG. 1B, the internetwork 20 includes a Network A, a Network B, a Network C, and a Network D. Each of these networks includes a special node that is distinguished by a circle. In FIG. 1B, the special nodes Node A, Node B, Node C, and Node D, are routers (but may be any of various types of nodes that interconnect two or more networks), and will hereafter be designated Router A, Router B, Router C, and Router D, respectively.
In one example, if Node C3 of Network C sends a packet to Node A1 of Network A, the packet must first be sent to Router C of Network C. Router C in turn, sends the packet to Router B of Network B. From Router B, the packet is sent to Router A of Network Router A, which delivers the packet to Node A1 of Network A. The nomenclature for how a packet is routed from one node to another between networks is often referred to as the “path” between nodes. Each element of a path is variously referred to as an “intermediary node,” an “intermediate node,” or more simply a “hop.”
Paths between nodes and routers can be formed dynamically or statically. Communication protocols, such as, Routing Information Protocol (RIP), Border Gateway Protocol (BGP), and Open Shortest Path First (OSPF) are examples of dynamic internetworking protocols that are used in IP internetworks.
FIG. 1C illustrates an internetwork from a point of view of a “sender” and “receivers”. Requests may be sent from the sender to the receivers via a gateway, which is an entry point to one of the receiver networks. A manifestation of the gateway may be, for example, a wireless access point. For example, the FIG. 1C internetwork may be a utility network 100 such as is shown in greater detail in FIG. 1D.
FIG. 1D is a generalized block diagram of a utility network 100. Utility network 100 may include one or more electronic devices 101. The electronic devices 101 may be connected over a wireless local area network (LAN) 102. As shown in the FIG. 1D example, multiple wireless LANs may be formed, which may or may not overlap, such that a given electronic device can be connected to (or be part of) only one wireless LAN or to multiple wireless LANs. The electronic devices may be any type of electronic device. Examples of electronic devices include utility nodes, which may include a utility meter or may connect to a utility meter.
A utility meter is a device which is capable of measuring a metered quantity, typically a commodity like electricity, water, natural gas, etc. Utility nodes which connect to a utility meter may include a network interface card (NIC) for communicating on a network, and may include one or more RF transceivers for communicating on one or more wireless LANs. Other examples of electronic devices include communication devices, such as set top boxes (as may be used in cable television or satellite television delivery), household appliances (e.g. refrigerator, heater, light(s), cooking appliances, etc.), computers or computing devices (e.g. game consoles, storage devices, PCs, servers, etc.), phones or cell phones, battery storage device, transportation devices, transportation vehicles (for example: an electric or hybrid car or other vehicle), entertainment devices (e.g. TVs, DVD players, set top boxes, gaming consoles, etc.), or other device which may be found in a home, business, roadway or parking lot, or other location. The electronic devices may, in some examples, perform as gateways, relays or perform other functions related to interconnecting devices. The wireless LAN 102 may be any type of wireless network, and may use any frequency, communications channel or communications protocol.
In some examples of a utility network, the LANs 102 are connected to one or more access points (AP) 103. A given LAN may be connected to only a single access point, or may be connected to two or more access points. The access points 103 may be connected to one or more wide area networks (WAN) 104. The WANs 104 may be connected to one or more back office systems (BOS) 105. For a utility, the back office system may handle a variety of business or management tasks, including participation in the collection of metering information, managing metering devices, security for the network, or other functions as may be desired in a utility network. Examples of back office systems include billing and accounting systems, proxy servers, outage detection systems (as may be used in a utility network), data storage systems, etc.
Nodes within the communications network, which may be a LAN or a WAN, or a combination of both, may communicate with other nodes using one or more protocols at various communication layers. For example, some nodes may communicate using IPv6, some may be communicate using IPv4, while some may communicate using both IPv4 or IPv6. Some nodes may communicate by encapsulating IPv6 packets in an IPv4 packet. Additionally, some nodes may establish an IPv4 tunnel through an IPv6 network.
Congestion control can be described notionally as controlling the rate of entry traffic of packets into a given network with the goal of maximizing ideal throughput between communicating nodes while avoiding congestive collapse. Congestive collapse is a condition where there is little or no useful communication happening because of congestion.
In a packet switched internetwork such as an IP internetwork, there are two popular methods by which congestion control can be achieved:                1. Routers Discard Packets. Routers in an internetwork perform congestion control by discarding packets sent by nodes that would otherwise cause the maximum packet or data rate between two routers to be exceeded. Such an example is found in the method described in the paper “Random Early Detection (RED) Gateways for Congestion Avoidance” by Sally Floyd and Van Jacobson.        2. Non-Router Nodes Perform End-To-End Congestion Control. A node may use congestion avoidance algorithms like Transmission Control Protocol (TCP) congestion avoidance, which performs congestion control between two non-router nodes in an IP internetwork. TCP congestion avoidance has multiple variations, including the variations TCP Reno, TCP Tahoe, and TCP Vegas. The paper “Simulation-based Comparisons of Tahoe, Reno and SACK TCP” by Kevin Fall and Sally Floyd is a useful reference as is the paper “Congestion Avoidance and Control” by Van Jacobson.        
Methods that are similar to the “Routers Discard Packets” method described above are not end-to-end congestion control models. “RED Gateway for Congestion Avoidance” by Sally Floyd and Van Jacobson describes a method by which routers and the intermediate hops of a path discard packets to enforce maximum link capacity.
Methods that are similar to TCP congestion avoidance, while end-to-end, do not consider the intermediate hops of an internetwork path as congestion points. In the TCP congestion avoidance technique, decisions on whether to send a packet are based on the communication success rate between two end-points in isolation.